GGI stands for "General Graphics Interface", and it is a project that aims to develop a reliable, stable and fast graphics system that works everywhere. We want to allow any program using GGI to run on any platform requiring at most a recompile.
OgrePx set the link between 3d engine Ogre and PhysX Physics System. WARNING! Now, there no any stable release, and I don't recommend you to download anything. Check it at July 2008.